To simplify the description, structural framework may be categorized as being fixed, semi-fixed, or temporary. The building type will determine the building codes and regulations to be met by the structure. Examples of fixed structural framing are those used for permanent buildings, this is where the building is intended to remain at the location of construction and is not designed to be moved. The joints may be bolted, riveted, welded or a combination thereof, the attachment method being determined by such factors as the design/approval requirements, accessibility and availability of equipment and skilled labor. Examples of semi-fixed structures include buildings used for temporary housing such as camps for the military and mining community where the buildings may need to be disassembled and moved for the camps to be relocated as and when required. The building may be connected as a permanent structure but have the ability to be disassembled. For this category the building joints should also consider being sized for transportation and capability of assembly, locking, disassembly and dependent on how often the structure is moved, wear and tear. Examples of temporary structure include scaffolding where the structure is designed to be easily assembled and disassembled using standardized components, fasteners and assembly equipment. The building codes will differ from those used for fixed and semi-fixed buildings. Additionally, the building structural components are designed with a weight and size that can be easily transported and handled at the construction site.
Currently, sustainability and “green building” is a leading driver of architectural design. Prefabrication introduces the ability to make things quicker, easier to assemble, and improve quality. Using engineered components with tight tolerance controls provisions the ability to make a tight structure with minimal gaps. The result of producing parts in a factory environment creates cost effective production of components that repeatedly fit together. With the use of analytical tools covering multiple design cases, the parts will be designed to meet the loading requirements, thereby redundant reducing material. The reduction in material waste along with the reduced manufacturing and transportation costs go a long way towards making the product and building structure more environmentally friendly and affordable.
The building industry, as with other industries, is taking advantage of “modular” type construction, where assemblies, sub-assemblies and components arrive at the construction site prefabricated. Time and cost reductions are made by delivering finished components to the construction site that may only require assembly, as opposed to fabricating or reworking components to fit on the construction site where access, day light and weather can affect both the construction quality and assembly times. The design is based around the utilization of advancements in design and manufacturing technology, which will now be discussed in further detail.
The construction industry, as with other industries, benefits from developments in new technology, manufacturing methods, materials and fasteners/fastening techniques. With developments in new technology come the ability to manufacture components/structures that were either not possible before due to manufacturing constraints or could not cost effectively be produced. An example of developments in new technology supporting manufacturing methods can be seen with the introduction of 3D (three dimensional) definition of parts where the drawing definition can be represented by an electronic definition of the part in ‘3D’ such as Initial Graphics Exchange Specification (IGES) or STandard for the Exchange of Product (STEP defined by ISO-I0303-21) model data file. These files contain vendor neutral data that allows digital exchange between different programs used for design, analysis and manufacture.
Programs such as SolidWorks and CA TIA to name two commercially available products are examples of industry standard software used for design and simulation. Describing CATIA (Computer Aided Three-dimensional Interactive Application) in more detail to provide an overview of the product; CATIA is a multi-platform CAD/CAM/CAE commercial software suite developed by the French company Dassault Systemes. Commonly referred to as a 3D Product Lifecycle Management software suite. CATIA supports multiple stages of product development (CAx), including conceptualization, design (CAD), manufacturing (CAM), and engineering (CAE). CATIA facilitates collaborative engineering across disciplines, including surfacing & shape design, mechanical engineering, and equipment and systems engineering. It also provides tools to complete product definition, including functional tolerances as well as kinematics definition and structural analysis.
Catia V5 is currently common place in the Automotive and Aerospace industries. 3D definition files may be used to fully define parts, subassemblies and assemblies, where along with the geometric definition of a component the material, production process, inspection and tolerance requirements can be defined in the notes of the electronic part or product file. Once the part is defined it can be used to define assemblies where multiple parts may be brought together to form a product. The same definition of the part may be saved in different forms so they can be used with different programs. Two of the forms commonly used by manufacturing equipment are IGES and STEP files described earlier.
Examples of developments in the manufacturing industry are supported by automated machinery. There are also cost, quality and production time benefits associated with the use of automated machinery for manufacture examples of such are water jet, laser cutting and robot welding machines, subsequent to setting the machine up, the machines may only require intermediate checks due to the self-monitoring ability of the machine. Quality control may be reduced to probability sampling of the components produced and checking the quality of the materials used for manufacture. Additionally, if the manufacturing/machining process is cost effective, additional holes or features can be added into the parts allowing the part to be used in multiple configurations. Reducing the number of part types, faster types and using standard sections all support a cost effective efficient manufacturing process. The use of robotics is common in the manufacturing industry, having manufactured accurate, close tolerance parts allows for accurate location of parts in tooling jigs and fixtures, provisioning for robotic welding where parts can be produced with repetitive quality.
By encompassing advancements in technology in building design enables improvements in environmentally friendly, sustainable “green buildings”, this is supported with efficient manufacturing methods and efficient use of materials. Automated machinery can reduce waste levels with inherent accuracy and programs such as those used to determine the most efficient cutting of part combinations to yield the most parts out of standard length of raw material.
Developments in the use of building materials can be seen in the materials used for building cladding such as Panelized finishing of structures, where both residential and commercial buildings are clad using easily installed energy efficient insulated panels mounted on railing systems such as pre-formed sheet metal and interlocking extrusions. The panels can be modified on site avoiding the necessity for transporting different panel types which have to be protected and traced. On-site modifications may include the panel being trimmed to suit the installation requirements or having apertures cut on site provisioning for doors, windows and accessories such as solar panels. Additionally there are developments in new materials; metallic, composites and combinations of both, one example being Structural composites bonded panel assemblies.
For example, developments in fastening systems, captive nut installations such as “Riv-nuts” where the nut is formed into the component(s) to be attached or a nut carrier plate that can be attached to the component(s) being attached allowing one sided installation or fastening to closed section structural component such as tube. Thread forming such as ‘flow drilling’ where the thread is formed in the base part or a nut ‘carrier plate’, along with developments in locking such as ant vibration washers and fastener systems.
In the design and manufacture of the building components, advances in design and analysis tools allows the ability to simulate and analyze designs in three dimensions with static and fatigue loading, using force, pressure, inertia and temperature loading in singular or combination load application. Thermal analysis tools can be used to aid the material selections, providing the benefits required for the environment to which the building will be subjected. This is beneficial in the analysis of the structure exposed to the effects of extreme weather. Structural and thermal analysis also support the “green building” approach by selecting the most suitable materials, the waste can be minimized by designing the structure to meet the loading requirements, this being done by designing an ‘efficient’ structure where the cross section of the load bearing members is designed to match the loading requirements. This type of design approach is typical in the aerospace industry, where the airframe structure is designed to closely meet the loading requirements, this is typically being done by creating a ‘Finite Element Model’ (FEM) of the complete aircraft structure. Industry standard programs such as MSC Patran (pre and post processor) and MSC Nastran are typically used to perform linear and non-linear structural analysis.